Prosthetic heart valves are used to replace diseased natural heart valves. Several categories of prosthetic heart valves are in existence. In prosthetic heart valves, one or more leaflets or occluders are carried within an annulus of the prosthesis and act as a valve to blood flow. The leaflet may be of a biological material or a synthetic material for bioprosthetics or, in a mechanical prosthesis, may be of a biocompatible material such as pyrolytic carbon.
One type of bioprosthetic heart valve is a stentless aortic tissue valve. Such tissue valves include a root version and a sub-coronary version. The root version includes an aortic root which is used to replace a diseased aortic root of a patient. However, in instances where the natural aortic root (or aortic arch) is healthy, the sub-coronary version may be used and the native root can be left intact.
In many instances, the surgeon will excise (or "sculpt") portions of the sinus areas of the prosthetic aortic root of the root version stentless aortic tissue valve to form a sub-coronary prosthesis. Often, this procedure must be done during surgery when operative time is limited. It is difficult to accurately sculpt the sinus areas and avoid damage to the leaflets due to lack of visibility of the inside of the heart valve. Currently, stentless aortic roots have been provided which include markings to aid in modifying the device from a full root replacement to a sub-coronary application. However, these markings are of only marginal assistance to the surgeon. One bioprosthetic stentless aortic root uses very unrefined surface indicators formed by sutures which are sutured through the tissue. Another stentless aortic root requires the surgeon to rely on sketches which are provided in surgical literature.
For other bioprosthetic devices, such as a valved conduit, the device must be oriented and implanted correctly with respect to blood flow direction. Still other bioprosthetic devices, such as pericardial patches, may require that the device be oriented and implanted in a particular manner. For example, it may be desirable to implant the patch so that the strongest axis of the device is aligned with the major stress axis. Other bioprosthetic devices, such as stentless mitral valves or mitral valve repair kits can be scaled (cut down) for a proper fit while maintaining proper geometry. Further, annuloplasty rings must be of the correct size for valve repair.